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Exh. 7-14S3-2 Revision Date: 12/13/22 <br /> Revision No.: TR-158 <br />Temporary Ditches <br /> <br />The Stoker Ditch routes water from native and disturbed areas to the Section 3 Ponds. The <br />location of the temporary ditch can be found on Map 12 and Figure Exh. 7-14S3-2. Design <br />information for the temporary ditch is as follows: <br /> <br /> Stoker Ditch <br />Station Peak Flow <br />(CFS) <br />Average <br />Slope <br />(%) <br />Channel Type Side <br />Slopes <br />Total <br />Depth <br />Erosion <br />Protection <br />0+00 to 24+86 19.06 3.0 V Ditch 2’ <br />Bottom Width <br />1H:1V Left <br />7H:1V <br />Right <br />0.5 Vegetation <br /> <br />Permanent Post Mine Channels <br /> <br />The Section 3 Pond watershed is comprised of two post-mining channels. The main channel is <br />the Streeter Ditch, which will convey post mining surface water flows to the Upper and Lower <br />Section 3 Ponds. Buckskin Ditch is a tributary to the Streeter Ditch. The locations of both <br />channels are presented on Map 12 and Figure Exh. 7-14S3-2, and the channel profiles are <br />presented on Map 33. <br /> <br />Both channels have been designed in accordance with Rule 4.05.4(2)(b) for the 100-year, 24- <br />hour storm event as the watershed reporting to the Upper and Lower Section 3 Ponds is greater <br />than one square mile. <br /> <br />A SEDCADTM model has been included which evaluates the peak flow and total runoff volume <br />for each of the channel segments for the 100 year, 24-hour storm event. The channel <br />configurations for the Streeter and Buckskin Ditches are summarized below. <br /> <br />Streeter Ditch <br />Station Peak Flow <br />(CFS) <br />Average <br />Slope (%) Channel Type Side Slopes Erosion <br />Protection <br />Station 0+00 to <br />SD-1 104.12 4.7 Trapezoidal 15’ <br />bottom 3H:1V Riprap, <br />D50 = 6” <br />SD-1 to SD-2 109.89 4.4 Trapezoidal 15’ <br />bottom 3H:1V Riprap, <br />D50 = 9” <br />SD-2 to SD-3 111.97 2.7 Trapezoidal 15’ <br />bottom 3H:1V Vegetation <br />SD-3 to <br />Confluence with <br />Buckskin Ditch <br />104.21 2.1 Trapezoidal 15’ <br />bottom 3H:1V Vegetation <br />Confluence of <br />Buckskin Ditch to <br />Station 101+46 <br />81.98 2.6 Trapezoidal 15’ <br />bottom 3H:1V Vegetation <br />